Stereophotogrammetric restorer



Aug. 4, 1953 v. D. GRoNDoNA STEREOPHOTOGRAMMETRIC RESTORER 15 Sheets-Sheet 1 Filed 001;. 31, 1950 4 INVENTUB Mmvm/aN/n/@a'o//wm ATTO RN EYS Filed Oct. 31, 1950 l5 Sheets-Sheet 2 P1 PIII C l l INVENTR YL Y Muff/r/NoM/HsonoA/pom argl g2 ATTORNEYS Aug- 4 1953 v. D. GRoNDoNA 2,647,318

STEREOPHOTOGRAMMETRIC REsToRER Filed oct. "s1, 195o 15 sheets-Sheet s ATTO RNEYS Alug- 4, 1953 v. D. GRoNDoNA 2,647,318

STEREOPHOTOGRMMETRIC RESTORER l Filed 001'.. 51, 1950 15 Sheets-'Sheet 4 I N V E N T D R MMM/Damme Gamm/v4 ATTORNEYS Al1g- 4, 1953 v. D. GRoNDoNA 2,647,318

sTEREoPHoToGRAMMETRIc REsToRER Filed oct. s1, 195o 15 Sl'leets-Sheetl 5 INVENTOR Aug. 4, 1953 v. D. GRoNDoNA STEREOPHOTOGRAMMETRIC RESTORER 15 Sheets-Sheet 6 Filed Oct. 5l, 1950 ATTORNEYS Aug 4, 1953 v. D. GRoNDoNA v 2,647,318

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sTEREoPHoToGRAMn/IETRIC REsToRER l Filed oct. s1, 195o 15 sheets-sheet s INVENTOR *Y luf/vm/ah//vao Gear/pom n ATTO RN E Y Aug. 4, 1953 v. D. GRONDONA STEREOPHOTOGRAMMETRIC 'RESTORER 15 Sheets-Sheet 9 Filed 0011. 51, 1950 Sw wkn ,En En mvENToR #um r/f/ J70/'Maa Gao/mm BY y ATTORNEYS Aug. 4, 1953 v. D. GRoNDoNA STEREOPHOTOGRAMMETRIC RESTORER 15 Sheets-Sheet l0 Filed OCT.. 3l, 1950 III www www mw sill. l... .il. IIIIPI-.S

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INVENToR V4! f/v rw aM/f/Go Gpo/wom BY ATTORNEYS V. D. GRONDONA STEREOPHOTOGRAMMETRIC RESTORER Aug. 4, 1953 15 Sheets-Sheet l1 Filed 001'.. 31, 1950 LNVENTOR UOM/N60 GffavzzaA/A ATTORNEY5 Aug- 4, 1953 v. D. GRoNDoNA 2,647,318

STEREOPHOTOGRAMMETRIC RESTORER Filed 001'.. 31, 1950 l5 Sheets-Sheet l2 INVENTOR lzmr/f/am/veo (iw/wom BY ATTORNEYS Aug. 4,1953 v. D. GRONDONA 2,647,318

STEREOPHOTOGRAMMETRIC RESTORER Filed 00t- 31, 1950 l5 Sheets-Sheet 13 82 85 w@ jg" LNVENTOR Mlm mDoM//Yco Gamm/m BY ATTORNEYS Allg- 4, 1953 v. D. GRoNDoNA 2,647,318

l STEREOPHOTOGRAMMETRIC RESTORER Filed Oct. 31, 1950 15 Sheets-Sheet 14 I N V E N T O R lzff/m/Don/Nqa @n0/wm BY ATTORNEYS V. D. GRONDONA STEREOPHOTOGRAMMETRIC RSTORER Aug. 4, 1953 15 Sheets-Sheet l5 Filed OCT.. 3l, 1950 ATTORNEYS Patented Aug. 4, T1953 UNITEDv STATES PATENT OFFICE Valentin Domingo Grondona, Rosario, Argentina Application October 31, 1950, Serial No. 193,090 In Argentina April 7, 1945 This invention relates to -a-stereophotogrammetric restorer which operates by solving an analytical formula by means of kinematic devices andv is continuation-impart of my application Serial No. 588,943, filed April 18, 1945, and now abandoned.

The knownA stereophotogrammetric rest-orers are very large in size and the correct operation thereof can only be performed by very skilled operators.

The stereophotogr'ammetric restorer according to the invention comprises a magnifying stereoscope and a stereoscopic photograph carrying platformboth in operative relationship with manually operable means for controlling azimuth, distance and elevation and with a drawing instrument in order to record the restoration to be made. [During the' following description and claims the magnifying stereoscopeN `will simply be called stereoscop'e; but it is understood vthat said stereoscope is preferably of "the type which at the same tim'ermagnies the images.

More particularly the present invention refers to a stereophotogrammetr-ic restorer comprising a first bridgeJ a stereoscope mounted on said first bridge and including a-leftv eyepiece and a right eye-piece located on either side of an axis of symmetry contained 'in a plane 'of symmetry perpendicular to said'rst bridge, a base frame supporting said .rst bridge and having two parallel basic bars spaced from each other and parallel to said .plane of symmetry, said basic bars .defining .a seeond plane perpendicular to said planey of symmetry, a transverse bar linkingsaid two basic bars, two upstan-ding supports each fixed to a respective basic bar in parallel relationship to said plane of symmetry, said basic bars supporting substantially the several parts of the apparatus, a stereoscopic photogram carrying platform parallel to said first bridge, .a first `manually -`o perable means for moving said platforinperpendicularly to the planel of symmetry, :a A.second manually operable means for moving platform parallel to said plariafsaid `first manually operable means `comprising anrst screw spindle supported said basicbars perpendicularly to saidplane of symmetry, anrst cursor slideably mounted. on said first screw spindle, a 'firs-trod constitutingza driving connection between-said first lcursor andfsaid platform, a hand-wheel for tunning said first :screw'spindlea first column and a 'second column slideably mountedone on each basic bar and 'supporting a second'bridge, a third-bridgea-fourth bridge, a 'ith bridge and 19 Claims. (Cl. 33-20) a sixth bridge, a third column and a fourth column mounted on said transverse bar and adjacent said two basic bars, said third and fourth columns supporting a seventh bridge and eighth bridge, a ninth bridge and also said first bridge, said rst and second columns being positioncontrolled by corresponding manually controlled, coupled second and third screw spindles, ,a second cursor coaxial with said first cursor and rotatably mounted thereon, a third cursor slideably mounted on said second bridge and provided with a second rod rotatably supporting a fourth cursor and afth cursor, said fifth cursor being slideably along said `third bridge. a bar having two end portions, one end-portion being slideably mounted in said second cursor and another end portion being slideably mounted on said fourth cursor, a rst pin pivotally supported by said seventh and eighth bridges, said' bar being pivoted to said first pin, a polar pantograph comprising a plurality of articulated meshes and having a pole, an actuating point and a writing point, a first block, a second pin, a graduated Acircular member being mounted on .said transverse bar, a guide lrotatably vmounted on said cir-- cular member, said rst block vbeing rectilinearly displaceable in said guide, said first block constituting a housing for said second pin, said pole v' of said pantograph being coupled tcfsaid second pin, said actuating point of said pantograph being coupled to said first rod, said second manually operable means comprising a fourth screw spindle provided with a hand-Wheel for manual control and supported by said first and second columns below said fourth bridge and above said third bridge, a sixth cursor mounted on said fourth vscrew spindle and displaceable along said fourth bridge, a seventh cursor pivotally linked to said sixth cursor and displaceable along said third bridge, a right yangle lever having a first arm and a second arm linked together by a second block, said second block being rotatably supported by said rst pin,` .said rst arm passing through said seventh cursor, each ofsaid upstanding .supports slideably supporting a bar arranged parallel to said ,upstanding support and .substantially parallel to `said stereoscopic photogram carrying platform, said bars being coupled together by two parallel :spaced .rails l,perpendicular to said plane, said stereoscopicv photogram carrying platform being provided with rollers -sli-deably mountedfon said rails, said second arm lof .said right angle lever being coupled to one. of said bars supported by said upstanding supports,

. `a stereoscopic parallax compensator means coupled to said stereoscope and to a link mechanism comprising a system of pivoted links forming a rhombus of variable angle including vertices dened respectively by a first pivot pin, a second pivot pin, a third pivot pin and a fourth pivot pin, said first pivot pin being coupled to said sixth bridge and said third pivot pin being connected to said ninth bridge and coaxial with said rst pin, a pair of additional links of equal length, a fifth pivot pin pivotally coupling together said additional links at one of their ends, the other ends of said additional links being connected respectively to said second and fourth pivot pins, said fth pivot pin being located on the side of said third pivot pin remote from said rst pivot pin and being connected to said movable stereoscopic parallax compensator means, a second bar having a rst portion fixed to said first bar and a second portion parallel to and vertically spaced from said rst bar, said second portion having g la fulcrum connected to said ninth bridge and coaxial with said first pin, a free end arranged in motion transmitting relationship with an eighth cursor slideably supported by said fth bridge, said eighth cursor being in operative relationvship with an angularly adjustable slideway supported by said fifth bridge and with a ninth 'cursor slideably connected to said fourth bridge.

From the foregoing it will be apparent that an object of the present invention is to provide an apparatus of reduced dimensions and weight which can be easily handled, transported and linstalled on any suitable drawing board.

Another obj ect is to provide an apparatus which shall be simple to opera-te, thereby eliminating all complications and uncertainty in connection with the way of operation of `the apparatus so that even a non-specialized surveyor can use it. A still further object of the present invention is to eliminate all empirical calculations in coninection with the setting and handling of the apparatus. l These and further advantages and objects of the present invention lwill become apparent in the course of the following description taken in connection with the accompanying drawings illustrating by way of example a stereophotogram- .metric restorer in two of its embodiments.

-scopica1ly with xed coplanar cameras.

Figure 2 is a diagram showing an arrangement of two cameras for surveying a terrain stereoscopically with two cameras, individually mov- :able about their respective optical centres.

Figure 3 is a draft illustrating the geometric analysis of the surveying operation on theA terrain.

Figure 4 is a draft showing the geometric layout of the operation of restoring a point of the terrain.

Figure 5 is a plan View of the schematic arrangement of the stereophotogrammetric restorer in accordance with this invention.

Figure 6 is a similar plan View as Figure 5 but showing the schematic arrangement of a simpli- .fied stereophotogrammetric restorer to be used for Acoplanar plates only. n

Figure '7 is a schematic perspective view of the structuralI embodiment of the-simplified appara- 4vtus of Figure 6.

" vFigure 8 is a lateral elevation of the more elaborate apparatus in its actual structural form (based on the schematic arrangement shown in Figure 5), as viewed from right hand side with ports.

Figure 12 is a section of the photogram supports, along lines XII-XII of Figure 1l.

vFigure 13 is a part-sectional front elevation of the horizontal platform supporting the photogram supports and Valso showing the supporting `means of said horizontal platform.

Figure 14 is a section along line XIV-XIV of 'Figure 13 with some parts omitted.

Figure l5 is a fragmentary sectional view taken along lines XV-XV of Figure 11, but in an enlarged scale.

Figure 16 is a section of the apparatus along line XVI--XVIlof Figure 8.

Figure 17 is a front elevation of Figure 8 but with some parts shown in section and other parts omitted.

Figure 18 is a part-sectional plan view similar to that shown in Figure 9, but with some elements in different positions and other parts omitted.

Figure 19 is a detail perspective view of the double microscope comparator.

Figure 20 is a detail schematic view in perspective of the level compensating means of the `THEORY or 'rmt S'rEREoPHoTooRAMME'raIc RsToRi-:R

0F THE PRESENT INVENTION (a) Surveying opemtons There are two fundamental ways of arranging the cameras for surveying a terrain stereoscopically, as shown schematically in Figures 1 and 2.

(i) In the arrangement shown in Figure 1 a left camera CL and a right camera Ca are rigidly mounted ona horizontal bar B1 rotatable about its center or pivot V. The left camera CL has an objective Or. and a photographic plate TL, and the right camera. CR has an 'objective Oa and a photographic plate Ta.

It is assumed for the purpose of this explanaftion, that the left and right objectives of the respective cameras can each take a field of 45. Therefore the left camera C1. will take a field represented by the triangle OHG, wherein O represents the optical center of the left objective Oi.;- gi and h1 represent the equivalent end points on the photographic plate TL of G and H on the terrain. Similarly, the right camera CR will take a field represented by the triangle O'HG, wherein O' represents the optical center of the right objective Oa; 91' and hi represent the equivalent end points" on the photographic plate Ta of G' and H' on the terrain.V Upon placing the photograms corresponding to plates TL and TR in a photocomparator it will be possible to perceive a stereoscopic image of the superimposed parts of the two fields OHG and O'HG,

that is to say'of ithe eldlcorresponding to triythe arrangement of barBli together with the cameras CL and CR is rotated about pivot V, for instance through 30 (angle fy), as shown in Figure 1 in broken lines. Triangle J1 H1 G1 which represents an area hereinafter called steroscopic area encloses point P. If desired, a succession of partially overlapping stereoscopic areas can be taken so as to obtainby subsequent composition, a complete view of a large field. yIn the case illustrated in Figure 1, it would be sufcient to take a third view in an intermediate position, between the two positions shown,` as by rotating the bar arrangement B1, CL, CR through 15 with regard to the rst position, and thereby it is possible to obtain larger composite fields than the stereoscopic fields the lenses -of the vcameras are per se able to capture in any one given position.

It is to be noted that by using the arrangements as described, the photographic plates of the left and right cameras are always coplanar. Furthermore the base of this arrangement of the left and right cameras would be the length of the segment determined by the position of the optical centers of the objectives of the two cameras. In other words in Figure 1 the base would be the segment OO', no matter what position the bar B1 occupies.

(ii) One form of the second way of arranging the cameras for surveying, has been schematically illustrated in Figure 2. This arrangement has also a left camera, identified by reference character KL, and a right camera Iii.. In practice these two cameras may be one and the same camera, and the views are then taken separately and at different instances. Since there is no mechanical linkage vbetween the two stations where the photographs are taken either by two or by one and the same camera, the distance existing between the two positions may be considerably larger than in the rst arrangement and thereby obviously a larger field may be captured. Each camera is rotatably mounted on its support, a tripod for instance. The cameras are first positioned with their optical axes perpendicular to the base line, as indicated bythe position shown in full lines which corresponds to the full line position of Figure 1, and therefore the same reference characters have been used for like elements.

The difference with regard to the rst arrangement described resides in the fact that in order to increase the eld, i. e. in order to be able to survey point P of the terrain, in this case each of the left and right cameras KL and KR, respectively, are turned about its own respective axis which passes through the optical centers O and O. The position shown in broken lines corresponds to a rotation of 30 (angle fy), similarly as in the case of Figure 1.

In this embodiment, it has to be noted that in the 30 position the plates TL and TR are not coplanarly but parallelly mounted. OO is the base In order to obtain calculated results in terms of cartesian coordinates, an origin isselected conveniently at the optical center of one of the objectives, for example the objective O belonging to the lefthand camera KL in the drawing. Or will therefore also be thel origin of the cartesian colordinates.- The axis of abscissae XOX' is -conveniently taken as parallel to the 6 plates TL and TR. Hence the axis of ordinates YOY' will be a perpendicular to the plates TL and TR passing through the optical center which is the origin O.

Since after rotation of both cameras KL and Ka through equal angles, the plates TL and TR remain parallel, but the line joining the optical centers O and O", that is to say the base OO is no longer parallel to the plates, and since the axis of abscissae is parallel to the plates by construction, 'the base OO will make an angle, say the angle y (in this instance of 30) with the axis of abscissae.

(iii) The analysis of the surveying operation which may be carried out with any of the arrangements described orsimiliar ones, is illustrated in Figure 3, in which the axes of coordinates illustrated in Figure 2` are shown after rotation of the Whole diagram about the origin O through an angle fy to the right in Figure `2 s0 as to bring the axes of coordinates parallel with the edge of the sheet. Also in Figure 3, for clearne-ss, the coplanar position of the plates has not been shown. A f

Furthermore in order that the discussion shall be applicable to all the practically possible interrelationships of positions of the two cameras, the line OO' in the diagram of Figure 3 and'similar figures, is to be understood as being the vertical projection on the horizontal plane of the real physical base dened by the actual position of the optical centers of the objectives. Thisprojection will be called the horizontal projection of the base. When the cameras or rather the optical centers are at the same level, said horizontal projection of the base has the same length as the base itself, but when the optical centers are so located at different levels that the line joining them, that is to say the base, makes an angle tb with `thevhorizon plane, then of course the horizontal projection of this base will have a length equal to base-cos ip. Remembering this, any necessary correction' to adjust the formulae in terms of the real basecan readily be made.

LHence also the term base as hereinafter used will mean either the real base for objectives of equal level, or the horizontal projection thereof, indiscriminately.

P represents again the point of the terrain to be surveyed.4 From the construction described it will be seen that the optical axis of the right camera 'KR (Fig. 2) is parallel to the axis of ordinates YOY which cuts the of abscissae XOX at C, and the optical axis of the left camera KL (Fig. 2) coincides with the axis of ordinate. The focal length f of the objectives is represented in Figure 3 by the intercepts OC and O'C. y

l The images of P will be respectively Ftleft) and P (right) on the plates TL and Ta. The azimuth angles Will simultaneously be a and On tracing through Oa line parallel to OP", this line intersects the left plate TL at P". Hereby the stereoscopic parallax? e of P is represented by the intercept PMP". n

If from P we draw the rays PP and PP passing respectively through O and vC and cutting the axis of abscissae at O and U respectively, they will form a triangle OPU which is similar to POP, so that: I

if the length of segment OO' represented in Figure 3 is b then ":b cos 'y On the other hand C"U.- CO' tan and c"o'=b sin y so that OU=b (cos 'y-i-tan sin fy) If the length of segment OP is d, from (1) We Let the coordinates of P be y; shown in Figure A3 as segments LP and OL; then:

:d cos a so that ll() With coplanar plates y vanishes, that is to say:

d: fb un 8 COS cx e (b) Restoring operations Referring now to Figure 4, with origin O a pair of orthogonal coordinates is drawn with an axis of abscissae XOX' and axis of ordinates YOY. A segment OO of length b forms with the axis of abscissae an angle fy of equal sense and magnitude as that which the plane of the left photogram TL (see Figures 1 to 3) forms with the base line, which angle was at the time measured, by means of a usual limb arrangement which is provided in either of the devices described in Figure 1 or 2. On tracing the ordinate from O' we obtain, on the axis of abscissae, the projection B.

Let it be assumed that the optical axis of OC (which represents the focal length f) of the left photogram TL' coincides with the axis of ordinates YOY', so that the optical center O of the objective coincides with origin O, therefore bearing the same reference character. (The manner in which this coincidence can be achieved in the practical apparatus will be explained hereinbelow.) Photogram T'L carries point P which is the image of the homologous point of the terrain to be restored. Azimuth angle a has been restored in P'OC. The difference of parallax e is established by means of a photocomparator, and thus eZPIPIH in abscissae. Consequently P"OC is the azimuth COS 0! substituting these equations in (3), we have:

b cos 'v l e f and therefore:

. l l :HLM (4) From B draw the ordinate BN to cut MS at N. Through this point N a straight line is drawn to form with MS an angle 7 and cut the axis of ordinates YOY at T; hence the length of TN will be b'=b. Y Y

From the point S draw a perpendicular to MS to cut TN produced at R; and through line R draw a line parallel to the axis of abscissae XOX to cut YOY' at L and P'S produced at P, which point P will be the restoredpoint, Whose ordinate is OL. The length of segment OL is y.

In fact:

and in turn NS :NB tan Since NB=Z We obtain:

y'=Z-{-l tan tan 'y that is to say Y z/=Z(1 tan tan 7) By relating Equations 4 and 5:

Assuming that the lengths of OP is d', the distance of P from O will be:

COSC! which, since it constitutes the coeilicient of proportionality between the magnitudes on the terrain and their homologues in the restorer, will for the practical :apparatus represent the Working 'scale on which the voperation ofthe scalef bearing 'members is based. In order to deterl paratus is conveniently provided, as will behere-y inafter explained.

could be expressed as and constitutes a proportionality factor which is carried out, structurally by means of a conjugated lever system interconnected by means of a variable coupling which defines the magnitude t. 1

In order to facilitate the understanding of r hcw this proportionality factor is structurally obtained, reference vis again made to Figure 5 in which a conjugated lever system comprises a first lever EF', which in the theoretical explanation represents the magnitude g; a second lever GlF", which in the theoretical explanation represents the magnitude i`;` a variable coupling, preferably by means of a cursor'I which couples levers EF 'and G"F". The variable distance existing between the intersection F'" of the longitudinal axis of the cursor I with lever EF' and the end F of said lever is the above mentioned magnitude t; a third lever GH", the vlength of Which in the theoretical explanation Will be represented by value gi. at G to lever G"F". The end H" of lever G'fH" is ccnipled suitably to one end of an arm Q guided for rectilinear reciprocation, the other end of which is suitably connected tothe right end of the photocomparator, as will be later ex- N plained. From the link system described, it will be clear that displacement of point J with `re spect to xed point Owill be transmitted to give a proportional displacement of said other end of arm` Q. After adjustment of the initial position Lever G"H is fixed 'The magnitude 10 -1 l: fb rezos 'y 4) is represented in the apparatus by the main diagonal of a .Peaucellier diamond-JAMDO (Figure 5, which will `be later explained)kl which Vdia-- mond satisfies the equation L Zw=m2n2 and therefore mL-n 2O zw (7) wherein l--O'M w==OJ m=AM=MD'=DJ=`JA n=AO=DO and since b e b F i: fb cos y and therefore 4 i m-1L fb cos w eF Thus the relation l@ of point J,1the distance JO will always vbe represented by the variable w. Now, the said link system is so designed that the distance through which said other end -of arml Q is displaced -consequently on displacement of J, shall ybe equal to e (stereoscopic parallax). Also the working scale to be adopted depends on the position fof vcursor I with'regard to levers EF' and GH and involves therefore the evaluation of t.

From this proportion of the link vsystem we have rst: f

therefore:

and cursor I of the conjugated lever or restorer system will correctly transmit the .movement thereof to the telescope objective which has to be compensated for the stereoscopic parallax. From (9) we obtain:

.l l-t1 substituting for B We have :Fmzi z j Tami Combining all constants of the instrument into one factor Although for the analytical demonstration of the apparatus the base OO' has been drawn, this is not done during the restoring step, as the magnitude l, instead of being obtained projectively from Equation 4, is determined kinematically by means of Equations '7 and 9, hence The apparatus 'which will hereinafter be described in greater detail has been built mainly of articulated levers so arranged as to substantially represent the diagram of Figure 4. In the process of restoring, which will now be described in connection with Figure 5 it will be apparent by implication that what has been schematically illustrated in Figure 5 corresponds substantially to Figure 4.

The images of both photograms TL and TR' are made to coincide stereoscopically with the marks of the grids of the stereoscope Which will be later described,y for which purpose the right hand side of the comparator can be contracted. This movement is caused by the lever arrangement FG"IIQ pivoted at G and governed by the lever EF by means of cursor I. Lever EF', in turn ispivoted at F and operated by the restorer system, the. center of which is located at point 

